/*
 * Copyright (c) 2007 innoSysTec (R) GmbH, Germany. All rights reserved.
 * Original author: Edmund Wagner
 * Creation date: 26.06.2007
 *
 * Source: $HeadURL$
 * Last changed: $LastChangedDate$
 * 
 * the unrar licence applies to all junrar source and binary distributions 
 * you are not allowed to use this source to re-create the RAR compression
 * algorithm
 * 
 * Here some html entities which can be used for escaping javadoc tags:
 * "&":  "&#038;" or "&amp;"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;" 
 */
package com.github.junrar.io;

import java.io.IOException;
import java.io.InputStream;

/**
 * DOCUMENT ME
 * 
 * @author $LastChangedBy$
 * @version $LastChangedRevision$
 */
public class ReadOnlyAccessInputStream extends InputStream
 {
  private IReadOnlyAccess file;

  private long curPos;
  private final long startPos;
  private final long endPos;

  public ReadOnlyAccessInputStream(IReadOnlyAccess file, long startPos, long endPos) throws IOException
   {
    super();
    this.file = file;
    this.startPos = startPos;
    curPos = startPos;
    this.endPos = endPos;
    file.setPosition(curPos);
   }

  @Override
  public int read() throws IOException
   {
    if (curPos == endPos)
     {
      return -1;
     }
    else
     {
      int b = file.read();
      curPos++;
      return b;
     }
   }

  @Override
  public int read(byte[] b, int off, int len) throws IOException
   {
    if (len == 0)
     {
      return 0;
     }
    if (curPos == endPos)
     {
      return -1;
     }
    int bytesRead = file.read(b, off, (int) Math.min(len, endPos - curPos));
    curPos += bytesRead;
    return bytesRead;
   }

  @Override
  public int read(byte[] b) throws IOException
   {
    return read(b, 0, b.length);
   }
  //
  // public void close() throws IOException {
  // file.close();
  // }
 }
